As data networks scale to meet ever-increasing bandwidth requirements, the shortcomings of copper data channels are becoming apparent. Signal attenuation and crosstalk due to radiated electromagnetic energy are the main impediments encountered by designers of such systems. They can be mitigated to some extent with equalization, coding, and shielding, but these techniques require considerable power, complexity, and cable bulk penalties while offering only modest improvements in reach and very limited scalability. Free of such channel limitations, optical communication has been recognized as the successor to copper links.
Optical communication systems have been widely adopted for applications ranging from internet backbone, local area networks, data centers, supercomputing, to high-definition video. Due to superior bandwidth and low loss, optical fibers are the medium of choice for transporting high-speed binary data. However, virtually all data processing is still performed in the electrical domain. This necessitates an electrical-to-optical conversion (EO) in transmitters and optical-to-electrical (OE) conversion in receivers. Robust EO conversion is simpler, since electrical signals in the transmitter can be relatively large and well-controlled to match characteristics of lasers or optical modulators. On the other hand, OE recovery is complicated by numerous optical loss mechanisms present in practical links as well as penalties incurred due to transmitter non-idealities such as finite extinction ratio (ER).
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.